At 75%, 50% and 25%, 2-3 a forming armorine will spawn (will be constructed). Each has appx 500k HP. These should be killed immediately, as soon as they begin construction as they can be eliminated before they start attacking.

For each a forming armorine that is not killed in time (within 45-50 seconds of spawning), A Shadow Armorine (93^^^, appx 650k health) will spawn and attack.